Freezer and cooled chamber construction of a cold-gas refrigerator



Nov. 13, 1956 c. o. JONKERS ETAL FREEZER AND COOLED CHAMBER CONSTRUCTIONOF A -(X)l..D--(.1$\"$ REFRIGERATOR Filed Jan. 6. 1955 am m \h w mm&

INVENTORS CORNELlUS OTTO JoNKeRs LEENDERT oz LANGE AGENT United StatesPatent FREEZER AND COOLED CHANIBER CONSTRUC- TION OF A COLD-GASREFRIGERATOR Cornelius Otto Jonkers and Leendert de Lange, Emmasingel,Eindhoven, Netherlands, assignors to Hartford National Bank and TrustCompany, Hartford, Conn., as trustee The invention relates to a cold-gasrefrigerator comprising a space of lower temperature and a space ofhigher temperature, these spaces being in open communication with oneanother through a freezer, which has a temperature of 40 C. or lessduring normal operation of the refrigerator, through a regenerator andthrough a cooler. The volume of each of these spaces may be varied byone or more piston-shaped bodies; in the machine a gas being invariablyin the same state of aggregation performs a closed, thermodynamic cycle.A cold-gas refrigerator is often termed a cooling machine operating onthe reversed hot-gas reciprocating engine principle.

These machines may be constructed in various ways, for example as adisplacer-piston machine, as a double acting machine, as a machine, thecylinders of which are at an angle to one another or as a machine, theworking space of which is combined with that of a hot-gas reciprocatingengine. By means of this type of refrigerator it is possible to bridgein one step a large temperature difference, for example of 100 C. It iseven possible, in certain cases, to bridge a still larger temperaturedifierence, for example of 230 C.

According to the invention it has been found that the cooling power ofthe machine varies to a great extent with the relationship between themagnitude designating the ratio between the stroke volume of the spaceof higher temperature and that of the space of lower temperature and amagnitude denoting the ratio between the absolute temperatures of thecooler and of the freezer. If the limits referred to below for therelationship between these two magnitudes are exceeded the cooling powerof the refrigerator will decrease materially as has been found fromexperiments, the conditions being otherwise the same.

Further, according to the invention, the refrigerator is proportioned ina manner such that to the quotient v of the stroke volume of the spaceof higher temperature and that of the space of lower temperature appliesthat v is at least 1+0.025 1- and at the most most '7', preferably atleast l-|0.10 1' and at the most 0.8 1', wherein 1' designates thequotient of the absolute temperature of the cooler and that of thefreezer.

The aforesaid values apply to the normal operation of the refrigeratorconcerned. In one embodiment of the invention the refrigerator isconstructed as a displacerpiston machine. The construction of this typeof refrigerator is particularly suitable to choose the desired strokevolume of the various spaces. With this kind of machine it is, forexample, not necessary for the two pistonshaped bodies moving up anddown in the machine to have the same stroke.

The invention will be described more fully with reference to oneembodiment.

The accompanying figure shows a cold-gas refrigerator constructed as adisplacer-piston machine. This machine comprises a cylinder 1 in which adisplacer piston 2 and a piston 3 move up and down with substantially2,770,109 7 Patented Nov. 13, 1956 constant phase difference. Thus thevolume of the space 4 of lower temperature, also termed the freezingspace, is varied. Also the volume of the space 5 between the displacerpiston 2 and the piston 2 and the piston 3, this space having the highertemperature and being also referred to as the cooled space, is varied.

The two spaces are in open communication with one another through afreezer 6, a regenerator 7 and a cooler 8. In the machine a gas, forexample hydrogen, is mainly expanded in the space 4 and mainlycompressed in the space 5.

The displacer piston 2 is coupled through a connecting-rod system 9 witha crank of a crank shaft 10, whereas the piston 3 is connected through aconnecting-rod system 11 with cranks of the same crank shaft. Therefrigerator is driven by an electric motor 12. I

Owing to the thermodynamic cycle performed in the machine the freezerassumes a low temperature, so that by means of this freezer a mediumlocated outside the machine may be cooled. This medium, for example air,may be supplied through an opening 13 to a condenser space 14, in whichit condenses at vanes 15 of the freezer 6, the condensate beingconducted away through a duct 16.

The temperature of the cooler 8 may for example be 300 K. and thetemperature of the freezer 6 may be for example K. The quotient of thetemperature of the cooler and of the temperature of the freezer istherefore In this case the magnitude v is at least l+0.025 4 is 1.1 andat the most, is 4. Preferably the magnitude v is at least 1+0.1 4 is 1.4and at the most 0.8)(4 is 3.2.

If the volume of the space of lower temperature is ccms., it may becalculated within which limits the stroke volume of the space of highertemperature must lie.

The magnitude v is the stroke volume of the space of higher temperaturedivided by the stroke volume of the space of lower temperature. In thiscase the volume of the space of higher temperature is at least 1.1)(100is ccms. and at the most 4x100 is 400 ccms., preferably, however, atleast 1.4 100 is ccms. and at the most 3.2)(100 is 320 ccms.

By proportioning the machine in a manner such that the volume of thespace of higher temperature lies within the said limits, it may beassured that the cooling power of the machine is not affected to anundesirable extent due to improper proportioning.

While I have shown and described the preferred embodiment of myinvention, it will be understood that the latter may be embodiedotherwise than as herein specifically illustrated or described and thatin the illustrated embodiment certain changes in the details ofconstruction and in the arrangement of parts may be made withoutdeparting from the underlying idea or principle of the invention withinthe scope of the appended claims.

What is claimed is:

l. A refrigerator of the type described provided with a first spacehaving a temperature lower than 40 C. and a second space having a highertemperature than said first space, further comprising a cooler, aregenerator, a freezer, said first and second spaces being in opencommunication with each other through said cooler, regenerator andfreezer, a cylinder means enclosing said first and second spaces, a gasof invariable chemical composition performing a closed thermodynamiccycle in said refrigerator, two pistons for reciprocation in saidcylinder means to thereby vary the volume of said gas in said spaces,said refrigerator being proportioned in such a manner that the quotientv of the stroke volume of the space of higher temperature and that ofthe space of lower temperature is equal to at least i+0.025 1' and atmost 1, wherein 7' denotes the quotient of the absolute temperatures ofthe cooler and the freezer.

2. A refrigerator of the type described provided with a first spacehaving a temperature lower than 40 C. and a second spaceihaving a highertemperature'than said first space, further comprising a cooler, aregenerator, a freezer, said first and second spaces being in opencommunication with each other through at least said cooler, regeneratorand freezer, a cylinder means enclosing said first and second spaces, agas of invariable chemical composition performing a closed thermodynamiccycle in said refrigerator, at least one piston for reciprocation insaid cylinder, means to thereby vary the volume of said gas in saidspaces, said refrigerator being proportioned in such a manner that thequotient v of the stroke volume of the space of higher temperature andthat of the space of lower temperature is equal to at least 1+0.025 'rand at most 7, wherein 1- denotes the quotient of the absolutetemperatures of the cooler and the freezer.

3. A refrigerator of the type described comprising said cylinder meansand forming therewith a first space and a second space, said spacesbeing adapted to receive a gas of invariable chemical composition, acooler, a generator, and a freezer connecting said first space to saidsecond space, said gas having during operation a temperature below -40C. when in said first space and a higher temperature when in said secondspace, "the quotient v of the stroke volume of said first space and thestroke volume of said secondv space being above l+0.025 r and below 1,wherein 7' indicates the quotient of the absolute temperature-of thecooler and the absolute temperature of the freezer.

FOREIGN PATENTS Australia Dec. 10, 1953

